USA pharma plants: Purdue model zones & firewall placement for OT security

The Purdue model is a simple way to segment plant networks so incidents don’t spread from IT to OT. Here’s how to apply it in pharma manufacturing.

Recommended zones

• Level 4/5: Enterprise IT

• Level 3.5: Industrial DMZ

• Level 3: Site operations (MES)

• Level 2: Supervisory (SCADA)

• Level 1/0: Controllers and field devices

Firewall placement checklist

• IT ↔ DMZ firewall with strict allow-lists

• DMZ ↔ OT firewall with protocol-aware rules

• Separate vendor remote access zone

• Log all admin access and configuration changes

Request a security assessment

Want a quick, practical OT-security gap check for your pharma plant? Submit the assessment request and we’ll respond within 1 business day.

Use the form: Request a Security Assessment

Related reading

Related: Secure remote access to OT — /post/secure-remote-access-to-ot-in-pharma-vpn-vs-ztna-and-what-auditors-expect

Related: IEC 62443 starter guide — /post/iec-62443-for-pharma-manufacturing-a-plain-english-starter-guide

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